Thyroid abnormalities in acromegaly in the era of improved disease control: a two-stage study

Acromegaly is associated with increased risk of diffuse or nodular goiter and possibly of thyroid cancer. The aim of this study was to verify whether these findings persist in the current scenario of improved disease control.

A two-steps protocol was carried out:. In the first (retrospective), clinical and laboratory data (including 969 IGF-I measurements), and the frequency of thyroid cancer were recorded for 92 acromegaly patients over a 28-year period. The annual control percentage was defined as the average of the ratios between each of the 969 IGF-I measurements over the total follow-up period and the respective upper age limit (IGF-I/ULN) less than 1.Acromegaly activity was determined at the last visit. In the second step (cross-sectional), 74 of the 92 acromegaly patients underwent thyroid ultrasound and were subjected to a two-stage cluster analysis, with the aim of grouping them into homogeneous clusters.

70% of the 92 patients had inactive disease, with a median control rate of 50%, with four cases of thyroid cancer (4.3%), only one in a patient with active disease. Two-thirds of the 74 patients (evaluated by ultrasound) had nodules, and 27% had diffuse thyroid hyperplasia. Three clusters were segregated with high significant differences in sex and echotextural alterations (p < 0.0001 in both cases). Age, number of nodules, thyroid volume and follow-up time were similar between the clusters.

No inherent thyroid changes were apparently identified in a large cohort of acromegaly patients. Better control during follow-up may attenuate thyroid manifestations in acromegaly.